Publication Name: The Sedimentary Basins of WA
Authors: N. B. Thompson, M. L. Taylor and N. C. Taylor
Publication Volume: 2
Date Published: December 1998
Number of Pages: 19
Reference Type: Book Section
Abstract:
The Perseus Field is a giant gas accumulation in a complex structural/stratigraphic trap. Gas is reservoired in Bathonian to Callovian deltaic sandstones of the Legendre Formation, which subcrop the Upper Jurassic-Lower Cretaceous 'Main Unconformity' in a graben separating the Goodwyn and North Rankin horsts.The extensive core dataset from Perseus 2, Perseus 3A, Perseus South 1 and Capella 1 has been invaluable in establishing a detailed chronostratigraphic model for the Perseus reservoir section. Six third-order depositional sequences have been identified within the W. digitata, W. indotata and C. halosa dinoflagellate zones.
Five main facies have been recognised in the Perseus cores: fully bioturbated, lower shoreface to offshore sandstones; fine to very coarse shoreface sandstones; thinly interbedded, delta front, fine to very fine, sandstones and mudstones; interbedded, shoreface fine sandstones and mudstones; and greensands.
The Perseus cores include both fully marine ichnofossil assemblages, indicative of offshore deposition, and physically stressed assemblages, supporting the interpretation of predominantly delta front and shoreface depositional environments.